1. Field of the Invention
The present invention broadly relates to the emergency treatment of victims suffering from shock and, more particularly, is concerned with an anti-shock treatment method and garment for sequentially applying pressure to the legs and abdomen of the victim to cause a "milking action" thereon which forces blood return to the heart.
2. Description of the Prior Art
The use of a garment for applying pressure to the extremities of a person and thereby control blood flow is known as shown by U.S. patents to Clark et al (U.S. Pat. No. 2,495,316), Vail (U.S. Pat. No. 3,659,593), Fowler et al (U.S. Pat. No. 3,856,008), Kaplan et al (U.S. Pat. No. 3,933,150) and Sandman (U.S. Pat. No. 4,355,632). The garments of Kaplan et al and Sandman are specifically directed to the treatment of shock.
Shock is a clinical state where the tissues of the body are not adequately perfused by blood and become hypoxic (low oxygen state). The treatment of shock is to increase the blood volume so that tissue perfusion is restored. The garments of Kaplan et al and Sandman, as well as such garment as the Military Anti-Shock Trouser (MAST), help in the treatment of shock in a number of ways. The anti-shock garments apply pressure to the victim's legs and abdomen in order to increase the blood return to the heart and to decrease perfusion of the lower body portion. The garments, to some degree, inherently stabilize leg and/or pelvic fractures. Splinting of fractures is not only beneficial from an orthopedic standpoint, but also prevents further blood loss from the fracture site. Finally, anti-shock garments apply pressure to internal and external bleeding sites in the lower portion of the body which helps stop bleeding.
However, present commercially-available anti-shock garments of the kind represented by the garments of these two patents and the MAST have two problems associated with their use. The most important problem which has been demonstrated in the case of the MAST garment is that it does not accomplish its major goal of mobilizing blood from the lower portion of the body effectively. Experiments have shown that only about one-quarter of the blood which exists in the legs alone is returned to the heart by use of the MAST garment. Two factors contribute to this poor result. First, pressure applied to the leg is probably not evenly distributed. This condition might be due to differences in the diameters of various portions of the leg. Also, the pressure on the thigh is generated sooner, and will usually be higher, than the pressure on the calf. Secondly, the pressure is not applied in a distal to proximal direction so that the blood is not "milked" from the legs and abdomen.
Another problem with most commercially-available anti-shock trouser garments is that they must be inflated in order to pressurize the system. Punctures in the garment bladders, hoses and foot pump as well as leaky valves result in the loss of air pressure. As a result, the garment loses clinical efficacy. Since broken glass and sharp rocks are often found at an accident site, this is an important consideration. Also, changes in temperature and altitude will alter the garment's pressure.
Consequently, a need exits for an improved anti-shock treatment technique and garment which enhances blood return to the victim's heart and avoids the above-mentioned problems associated with presently available garments.